What causes pet periodontal disease?

What causes pet periodontal disease? Pet periodontal disease starts when bacteria form plaque on the teeth. Within days, minerals in the saliva bond with plaque to form tartar, a hard substance that adheres to the teeth. The bacteria work their way under the gums and cause gingivitis, which is an inflammation of the gums. These bacteria can then travel in the bloodstream to infect the heart, kidneys and liver.